Calcium reacts rapidly with cold water to give off hydrogen gas and form a white precipitate called calcium hydroxide as shown in the equation below. Which element could substitute calcium and react more vigorously?

sodium

Explanation:

sodium is a group 1 metal it has a higher reactivity than calcium

no

explanation:

go away, people want answers, not to hook up

answer: -

reaction:

na + cl ⇌ nacl

balanced chemical equation:

na + 2cl ⇌ nacl2

sodium + clorine goes to form sodium chloride (table salt).

the product is nacl2.

and the reactants are na and cl.

(note: if you don’t know what ⇌ means, read below: -

⇌(double head arrow) means reversible reaction).